Engineers present update to Ames flood study

A combination of solutions, outlined during public meetings earlier this week, will be recommend to the Ames City Council to combat flooding in the city.

A combination of solutions, outlined during public meetings earlier this week, will be recommend to the Ames City Council to combat flooding in the city.

The city called for the study in response to the flooding in 2010 that inundated South Duff Avenue and parts of the Iowa State University campus, including Hilton Coliseum.

The latest findings of the continuing study were presented during two meetings Wednesday at the Hilton Inn Ames Conference Center on University Boulevard. A number of workshops, public meetings and open houses have been held to date.

Andrew McCoy, water resources engineer for HDR Engineering Inc., reviewed a number of alternatives that were considered as ways to combat the effects of flooding. They were placed into three categories: storage, protection and non-structural.

“There’s a lot of alternatives that could prevent flooding but they’re extremely expensive,” he said at the first of the two meetings. “Then, there’s others that are less expensive and could be combined together that might make an economically feasible flood protection project.”

The solutions ranged from levee protection; conveyance improvements, which involve river channel improvements or removing bridge obstructions; and storage and conservation methods in the watershed.

Consultants analyzed the possible solutions using several criteria, including construction costs and a cost-benefit comparison, environmental effects and what level of protection each measure would provide, McCoy said. He also said there could be consideration given to modifying the city’s floodplain ordinance.

McCoy also addressed a number of questions asked by the public, including whether floodplain development was causing an increase in flooding.

McCoy said models created by consultants showed that if every piece of land was developed to the city’s standards, it would add a rise of 1 foot to a 100-year flood event, and 3 feet to a 500-year event.

“I highly disagree,” audience member Marianne Todey said of the minimal effect development has had on flooding.

Todey was not alone in her feelings among those in the audience.

She said she has lived in Ames since 1987 and has been concerned for a number of years about the impact South Duff Avenue development on flooding. She said the way to mitigate flooding effects would be to limit the amount of development there and encourage more on the west side of Ames.